test(e2e): wait for Pierre navigation to settle

[hermes-tomczyk]

Summary

• stabilize the flaky Git-mode panel-card scroll assertion by waiting for the Pierre review scroller to settle before resolving the inline card
• use the existing hit-test-aware navigation helper for prev/next buttons so clicks are not attempted while Pierre temporarily disables pointer events during re-layout

Evidence

Recent failed runs showed nondeterministic Pierre/virtualized-list behavior rather than ordinary assertion failures:

• run 36985673514: Linux e2e failed comments-panel.spec.ts:146 with toBeInViewport ratio 0; the same branch later passed in run 36987382541.
• run 36984324615: Windows e2e-windows (1) failed the same panel-card scroll and a navigation click timeout.
• run 36979019731 and run 36978689792: repeated Windows failures showed the same viewport/virtualization symptoms.

Root cause and fix

Pierre virtualizes files and temporarily disables pointer events while the review list re-layouts after navigation. The affected tests asserted or clicked immediately after a scroll/navigation request. This change synchronizes with the existing waitForScrollStable and clickWhenHittable helpers without weakening assertions, retries, or changing production behavior.

Tests

• Pre-commit checks: passed (gofmt, golangci-lint, Go tests, ESLint, Stylelint, CSS checks).
• npx playwright test test/e2e/tests/comments-panel.spec.ts test/e2e/tests/comment-nav.spec.ts --project=git-mode --list: passed (40 tests discovered).
• npm run test:frontend: one pre-existing unrelated failure in edit-reply-font.test.js requiring crit-web/assets/css/app.css; the other 644 tests passed.
• Full browser E2E was not run locally because Go is unavailable in this macOS workspace.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.62%. Comparing base (406875d) to head (82f7c4f).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1017      +/-   ##
==========================================
+ Coverage   75.61%   77.62%   +2.00%     
==========================================
  Files         161      168       +7     
  Lines       23474    23616     +142     
==========================================
+ Hits        17750    18331     +581     
+ Misses       4314     3875     -439     
  Partials     1410     1410              

Flag	Coverage Δ
e2e	27.02% <ø> (?)
unit	75.61% <ø> (+<0.01%)	⬆️

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